The valve of this invention is applicable to the flow of fluids, whether they be gases or liquids, and it has many applications.
One such application is a valve through which water is taken up from the bottom of a reservoir or from some other source of water and is used in a combustion control system such as that described in my U.S. Pat. No. 4,270,508 issued June 2, 1981. In that invention the total pressure in the exhaust system of an internal combustion engine is employed, among other things, to create suction to draw in water from a water reservoir at a rate depending on the exhaust manifold static plus velocity head near one cylinder to aid in obtaining better combustion of the fuel in the engine. The conduit leading from the water reservoir may be several inches long, often several feet long, and may extend well above the water reservoir. It is highly desirable in such an instance to maintain water in that conduit, so that water is drawn from it as soon as the device control pressure increases above a certain threshold value. Otherwise, the lapse of time before water would be provided to the engine combustion system would result in delayed response while extra dry air would be sucked in, giving quite different combustion performance.
The present invention, as applied to this combustion control system, may be used with an intake near the lowest end of the conduit, inside the water reservoir and at the bottom of that reservoir. The invention provides a valve either inside or outside the reservoir. It enables the flow of water from the reservoir (or other source of water) into the combustion system, and in its check-valve function it assures that water is always retained in the conduit leading from the reservoir, including the times when the engine is not running and when the intake manifold pressure is above a threshold level, so that the water is available for immediate supply to the induction system of the engine when the engine demands it.
It is also desirable to control the flow of water into the combustion control system, increasing that flow in accordance with increasing pressure differential, i.e., with the changes in the device control pressure, at least up to a certain point. The valve of this invention enables that to be done also.
Another feature of the system shown in U.S. Pat. No. 4,270,508 is the desirability of reducing the flow of water into the engine induction system when the pressure differential rises above a predetermined amount. The valve of this invention enables that to be done also. Alternatively, the valve can hold the flow at a constant rate above a predetermined pressure differential, or it can let flow increase at a much slower rate.
In U.S. Pat. No. 4,270,508, the water ejector is sized to match the cubic-inch displacement and power of the engine. The apparatus shown there is not able to satisfy fully the flow requirement at full throttle and still supply the flow needed at a part-throttle steady state and also the flow rate and flow rate changes during acceleration from part-throttle to full throttle. The valve of the present invention solves this problem.
As stated above, the valve is not limited to use in a combustion control system, but such a system is an example of one important use.
When a valve of the type of this invention is used under the hood of a car, it is subject to rising and falling temperatures associated with the driving and parking of the car. This creates a heat-soak problem. When the car is warm and the valve is also warm, it functions as a check valve and flow control device, as previously mentioned. Plastics such as polypropylene that may be used to mold the valve's body have a higher coefficient of expansion than does stainless steel, which may be used in a ball and in a ball-valve embodiment of the invention. As a result, when the car engine is turned off, and the valve assumes its check valve function, the metal ball is urged towards its plastic sealing seat, which is then enlarged due to its expansion by heat. As the car engine and the valve cool, there is a relatively large contraction of the plastic body, while the ball is held in place. This tends to cause the ball to become stuck, so that the valve remains sealed until it is again reheated and the plastic body again expands out from the ball. This action has some desirable features, but it also has undesirable features. One purpose of the present invention is to overcome the undesirable features while retaining the desirable ones.
Another feature of the invention is the novel method by which certain elements of the invention are manufactured. These elements are molded from certain types of plastics. It is highly desirable, and usually necessary, for certain cylindrical elements of the valve to have a uniform wall thickness. Earlier systems were unable to provide uniform flow under these conditions. This has been difficult to insure in most molding processes for these plastics, because the materials are typically sent into the mold in such a manner that they tend to be a little thinner on one side of the cylindrical element than on the other, so that the inner periphery is out-of-round. The present invention enables the production of a uniform part and of a cylindrical wall of uniform thickness by providing a novel method for throttling the flow of plastic into the part, so that the plastic is forced into the part at a uniform rate rather than flowing in to some portions preferentially. As a result, the invention obtains a uniform packing or filling of the mold and therefore a uniformly round part.